2-Oxo-1,2-dihydro­pyridine-3-carboxylic acid

The title compound, C₆H₅NO₂, a tautomer of 2-hydroxy­nicotinic acid, adopts a planar conformation. An intra­molecular O—H...O hydrogen bond of 2.504 (2) Å is found. The compound forms one-dimensional hydrogen-bonded chains along the [01] direction via an inter­molecular N—H...O hydrogen bond of 2.810 (2) Å.

Key indicators

• Single-crystal X-ray study
• T = 90 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.045
• wR factor = 0.130
• Data-to-parameter ratio = 14.2

checkCIF/PLATON results

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PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
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   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
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Computing details

Data collection: COLLECT (Nonius, 2002); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXL97 and local procedures.

2-Oxo-1,2-dihydropyridine-3-carboxylic acid

Crystal data

C6H5NO3	Dx = 1.621 Mg m^−3
Mr = 139.11	Melting point = 532–535 K
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 3.640 (1) Å	Cell parameters from 1370 reflections
b = 11.584 (3) Å	θ = 1.0–27.5°
c = 13.565 (3) Å	µ = 0.13 mm^−1
β = 94.64 (1)°	T = 90 K
V = 570.1 (2) Å^3	Prism, colourless
Z = 4	0.30 × 0.20 × 0.15 mm
F(000) = 288

Data collection

Nonius KappaCCD diffractometer	1307 independent reflections
Radiation source: fine-focus sealed tube	971 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
Detector resolution: 18 pixels mm^-1	θmax = 27.5°, θmin = 2.3°
ω scans at fixed χ = 55°	h = −4→4
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997)	k = −15→15
Tmin = 0.961, Tmax = 0.980	l = −17→17
2539 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.130	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0761P)^2 + 0.1679P] where P = (Fo^2 + 2Fc^2)/3
1307 reflections	(Δ/σ)max < 0.001
92 parameters	Δρmax = 0.33 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C2	0.5633 (4)	0.25484 (14)	0.33937 (12)	0.0161 (4)
C3	0.4124 (4)	0.18122 (14)	0.41096 (12)	0.0149 (4)
C4	0.3141 (4)	0.06996 (14)	0.38714 (12)	0.0160 (4)
H4	0.2153	0.0222	0.4354	0.019*
C5	0.3568 (4)	0.02535 (15)	0.29270 (12)	0.0185 (4)
H5	0.2937	−0.0524	0.2768	0.022*
C6	0.4913 (4)	0.09673 (15)	0.22447 (12)	0.0179 (4)
H6	0.5201	0.0685	0.1598	0.021*
C7	0.3601 (4)	0.22936 (15)	0.51047 (12)	0.0175 (4)
N1	0.5846 (4)	0.20702 (13)	0.24719 (10)	0.0174 (3)
H1	0.6636	0.2508	0.2003	0.021*
O8	0.4619 (4)	0.33727 (10)	0.52644 (9)	0.0218 (3)
H8	0.5445	0.3644	0.4752	0.033*
O9	0.2246 (3)	0.17228 (10)	0.57449 (8)	0.0216 (3)
O10	0.6713 (3)	0.35672 (10)	0.35588 (9)	0.0209 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C2	0.0139 (8)	0.0182 (9)	0.0161 (8)	0.0024 (6)	0.0007 (6)	0.0022 (7)
C3	0.0129 (8)	0.0182 (8)	0.0136 (8)	0.0011 (6)	0.0009 (6)	0.0015 (6)
C4	0.0126 (7)	0.0188 (9)	0.0167 (8)	0.0014 (6)	0.0018 (6)	0.0031 (6)
C5	0.0177 (8)	0.0174 (9)	0.0202 (9)	0.0015 (7)	0.0003 (7)	−0.0016 (7)
C6	0.0172 (8)	0.0213 (9)	0.0149 (8)	0.0040 (7)	0.0000 (6)	−0.0025 (7)
C7	0.0165 (8)	0.0191 (9)	0.0168 (8)	0.0025 (6)	0.0000 (6)	0.0004 (7)
N1	0.0181 (7)	0.0207 (8)	0.0136 (7)	0.0002 (6)	0.0034 (5)	0.0030 (5)
O8	0.0286 (7)	0.0202 (7)	0.0168 (6)	−0.0013 (5)	0.0038 (5)	−0.0020 (5)
O9	0.0269 (7)	0.0232 (7)	0.0154 (6)	0.0014 (5)	0.0066 (5)	0.0014 (5)
O10	0.0242 (7)	0.0170 (7)	0.0217 (6)	−0.0017 (5)	0.0031 (5)	0.0018 (5)

Geometric parameters (Å, º)

C2—O10	1.258 (2)	C5—H5	0.9500
C2—N1	1.376 (2)	C6—N1	1.351 (2)
C2—C3	1.435 (2)	C6—H6	0.9500
C3—C4	1.369 (2)	C7—O9	1.2264 (19)
C3—C7	1.487 (2)	C7—O8	1.317 (2)
C4—C5	1.402 (2)	N1—H1	0.8800
C4—H4	0.9500	O8—H8	0.8400
C5—C6	1.362 (2)
O10—C2—N1	119.98 (14)	C4—C5—H5	121.0
O10—C2—C3	124.63 (14)	N1—C6—C5	121.11 (15)
N1—C2—C3	115.40 (15)	N1—C6—H6	119.4
C4—C3—C2	120.45 (15)	C5—C6—H6	119.4
C4—C3—C7	121.13 (15)	O9—C7—O8	121.29 (15)
C2—C3—C7	118.41 (15)	O9—C7—C3	121.94 (15)
C3—C4—C5	121.11 (15)	O8—C7—C3	116.77 (14)
C3—C4—H4	119.4	C6—N1—C2	123.82 (14)
C5—C4—H4	119.4	C6—N1—H1	118.1
C6—C5—C4	118.03 (16)	C2—N1—H1	118.1
C6—C5—H5	121.0	C7—O8—H8	109.5
O10—C2—C3—C4	−177.69 (15)	C4—C3—C7—O9	−0.7 (3)
N1—C2—C3—C4	2.5 (2)	C2—C3—C7—O9	178.23 (15)
O10—C2—C3—C7	3.4 (2)	C4—C3—C7—O8	−179.82 (15)
N1—C2—C3—C7	−176.41 (14)	C2—C3—C7—O8	−0.9 (2)
C2—C3—C4—C5	−0.2 (2)	C5—C6—N1—C2	2.0 (2)
C7—C3—C4—C5	178.73 (15)	O10—C2—N1—C6	176.74 (15)
C3—C4—C5—C6	−1.5 (2)	C3—C2—N1—C6	−3.5 (2)
C4—C5—C6—N1	0.6 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O9^i	0.88	1.95	2.8100 (18)	164
O8—H8···O10	0.84	1.72	2.5040 (17)	154

Symmetry code: (i) x+1/2, −y+1/2, z−1/2.